The construction industry is increasingly moving towards a circular economy to reduce carbon emissions and minimize material waste. Wood’s renewable nature and its ability to store carbon dioxide makes it both a relevant and preferable material for sustainable construction. By reusing timber in new construction, we can achieve to limit the environmental impact and enhancing a more sustainability construction industry. However, classifying the structural properties of salvaged timber is a significant challenge.
Non-destructive testing techniques for timber properties have been developed over decades, but their application to reclaimed wood is relatively new. There is a lack of legislation and procedures for effectively documenting the quality of salvaged timber for reuse. Our project aims to establish guidelines for evaluating reclaimed timber.
The motivation for this work is driven by the potential to significantly reduce waste and environmental impact by reusing sound timber materials in construction. We are developing and testing procedures that provide reliable information on the properties of reclaimed timber. We aim to develop robust procedures to be applied in various building site scenarios. Identifying common defects and conditions that are decisive for the strength properties of timber elements, is essential for establishing procedures. The procedures should comply with standards of safety and the quality documentation of timber prior to reuse.
We conducted a pilot-scale laboratory study to explore the potential of non-destructive testing methods to achieve this aim. We used the ultrasonic pulse velocity and the vibration methods in conjunction with the 4-point bending test on 17 timber samples of reference and reclaimed timbers. Our studies demonstrated a good correlation between bending test results and non-destructive testing measurements. Our findings suggest that approaches for assessing new timber can be successfully applied to reclaimed timber, as demonstrated on a small scale, considering the additional complexity of reusing wooden material. We recommend non-destructive estimation of bending properties combined with visual assessment as a potential procedure for assessing the quality of reclaimed timber. We are using the Nordic standard of visual grading and the draft of the upcoming Norwegian standard for evaluation of recycled wood as a starting point in our development and study of visual assessment of reclaimed timber.
Keywords: reclaimed timber, non-destructive testing (NDT), visual assessment
Authors
Frederikke Petersen
DTU Sustain, Technical University of Denmark, Denmark
Serkan Karatosan
DTU Sustain, Technical University of Denmark, Denmark
Lisbeth M. Ottosen
DTU Sustain, Technical University of Denmark, Denmark
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